Bunsen burner for gas appliances, more particular for gas water heaters



Nov. 29, 1966 G. HElN ET AL 3,288,198

BUNSEN BURNER FOR GAS APPLIANCES, MORE PARTICULAR FOR GAS WATER HEATERS Filed Oct. 25, 1963 Fig.1 Fig.2

United States Patent 3,288,198 BUNSEN BURNER FOR GAS APPLIANCES, MORE PARTICULAR FUR GAS WATER HEATERS George Hein, Huclreswagen, and Erich Tropp, Remscheid, Germany, assignors to Joh. Vaillant K.G., Remscheid, Germany Filed Oct. 23, 1963, Ser. No. 318,269 Claims priority, application Germany, Oct. 30, 1962, V 23,215; Apr. 13, 1963, V 23,939 5 Claims. (Cl. 158-116) The present invention relates to a Bunsen burner for gas appliances, and more particularly to a burner for gas water heaters which can :be used with any type of gas such as city gas, mixed or liquid gas and the like. As is well known, the difficulty encountered with gas burners which burn various fuels resides in the fact that the gases have different ignition velocities; and therefore, the rate of flow at the burner opening should be small with gases having a low ignition velocity and high with gases having a large ignition velocity so as to avoid in the first case a lifting, and in the latter case a flashing back of the flame. In order to eliminate the difliculties encountered with the different ignition velocities, it is known to provide means at the burner opening for a locally restricted reduction of the rate of flow of the gas. Thus, the burner opening is so dimensioned that the rate of flow required for gases having high ignition velocity is pre-set, however, with gases having low ignition velocity the rate of flow is reduced in a locally restricted area to snchextent that in the area of the burner opening a lifting of the flame does not take place. Because the partial flames do not lift (adhering flames), better conditions of ignition are provided, and a lifting of the flame is avoided when gases having low ignition velocity are used.

The known means for locally restricting the rate of flow comprises baflie plates which protrude into the gas flow and act as retarding surfaces whereby a turbulence of the outflowing gasair mixture is effected with a consequent loss of energy of flow.

The present invention is based on the knowledge that such a reduction of the rate of flow may also be effected in a still simpler manner without baffle plates. The invention involves a burner tip having a gas outlet slot at each end of which impressions or depressions are provided, these impressions being intersected by the gas outlet slot so that in the area of the intersected impressions gas passes out of the slot in converging directions and a turbulence is created thus locally reducing the rate of flow. It has been shown that the flame does not lift any more above such impression intersected by the gas outlet slot so that there is existing a firmly adhering partial flame, even with gases having low ignition velocity.

For gas water heaters it is advantageous to utilize a gas burner wherein a plurality of parallel slot-shaped gas outlet openings are provided. Such burners also make it possible to burn gases having high ignition velocity without a flashing back of the flame taking place, provided the gas outlet slots are narrow enough. In order to thereby obtain a sufficient total outlet area in cross-section, it is necessary to provide a plurality of gas outlet slots spaced a small distance apart, however, still taking into consideration that the distance should be large enough so that sufficient secondary air may reach the individual flames.

If such a Bunsen burner includes a distribution chamber with a sheet metal part as cover plate, which is provided with a plurality of parallel gas outlet slots being arranged in the same plane, then it is expedient to have grooves provided in the sheet metal part perpendicularly to the gas outlet slots, which are intersected by the gas outlet slots. Such grooves may have semicircular or V-shaped cross-section. They add substantially to a strengthening 3,288,198 Patented Nov. 29, 1966 of the sheet metal part. The gas mixture is expelled from the burner into the groove from both inclined or curved sides, where a turbulence is effected so that, by Way of the groove, the rate of flow of the gas mixture is reduced. Therefore, above such groove, adhering flames are produced which do not lift even with relatively poorly igniting gas. Since the gas outlet slots are very close to each other, it may, however, occur that the adhering flames will impede the secondary air supply to the burner flames inasmuch as the adhering flame is enlarged in plan view, for instance, approximately circular, whereas the flame produced above the gas outlet slots forms a narrow flame strip in plan view. It is obvious that the enlarged or circular adhering flames prevent the secondary air entering from the sides from reaching the flame strips. Therefore, in the presence of such adhering flames at both sides of the gas outlet slots the distance of the gas outlet slots would have to be increased undesirably so as to ensure suflicient secondary air supply.

In further modification of the invention the increase of the slot distances is avoided for two adjacent gas outlet slots by providing only two adhering flames burning at opposite sides. This configuration permits the number of the adhering flames to be reduced by half without affecting the adhering effect. The secondary air supply to the flame strips is thereby ensured even in the situation where close slot spacing is used.

The invention may be realized in such manner that for each second gas outlet slot adhering flames are provided on both sides. It is, however, also possible to provide one adhering flame for each gas outlet slot, which with the one gas outlet slot is located at one side and With the neighboring gas outlet slot at the other side thereof. Instead of continuous grooves, individual cupshaped impressions must then be provided which are intersected by a respective burner slot in the manner as described.

An embodiment of the invention is presented in the drawings and described as follows:

FIG. 1 is a section through the burner tip;

FIG. 2 is the side elevation of a cutoff portion of the burner tip;

FIG. 3 is a plan view of the burner tip provided with slots;

FIG. 4 is a further embodiment of the invention in plan view;

FIG. 5 is an enlarged view of portions of the burner shown in FIG. 1; and

FIG. 6 is a cross-sectional view of the impression 10 as shown in FIG. 4.

The mixing tube body of the burner consists of cupshaped sheet metal parts 2 and 3 being connected with each other by rabbeting as at 4. The gas-air mixture coming from a distribution chamber V passes out through the slots 12 of the cover plate 11. The cover plate 11 closes off the distribution chamber towards the top, is of U-shape, and is supported by its legs 11' and 11" on longitudinal grooves 2 and 3' protruding inwardly, these grooves being impressed into the cup-shaped sheet metal parts 2, 3.

At both sides of the cover plate 11 provided with slots 12, grooves R are impressed into the opening face of the cover plate 11, said grooves having semicircular or V-shaped cross-section. The slots 12 intersect the grooves R so that openings are formed in the sides R and R Coming from the distribution chamber V the gas mixture also enters laterally, as is indicated by the arrows a and 0, through the sides R and R into the groove R. In the groove R, converging partial flows therefore meet, leading to a turbulence. Therefore, above the groove R the rate of flow is smaller than above the remaining portion of slot 12. Therefore, the end flames 17 produced above the grooves R continue to adhere at the burner tip in the case of gases inclined to lifting. The direction and the intensity, respectively, with which the partial flows meet depends on the inclination of the sides R and R that is to say, on the depth of the groove R. As a certain gas mixture quantity may also distribute in a longitudinal direction of the groove R, the end flames 17, as is illustratedin FIGS. 2 and 3, are subjected to a certain enlargement with respect to the main flame standing above slot 12.

It is expedient not to extend the slot 12 completely to the edge of the cover plate 11 so that with the radii of curvature extending into the perpendicular legs 11' and 11", as well as with the following thicknesses of the cups 2 and 3, a distance between the end flames (17), secondary air rising exteriorly at the burner body is produced.

The cover plate 11 is held in place by means of bent brackets L and L forming a part of sheet metal cups 2 and 3. As can be seen in FIG. 3, these brackets L, L are expediently arranged between two burner slots 12. In the embodiment illustrated in FIG. 4, cup-shaped impressions 10, of the cover plate 11 are provided at the ends of the gas outlet slots 12, 12, and are intersected by the slot ends. The impressions are missing with the interposing gas outlet slots 12". In the impressions 10, 10, as is illustrated in FIG. 1, the gas is passing out in converging directions so that the rate of flowing out is reduced at these locations whereby adhering flames 13, 13 are produced which do not lift. The adhering flames 13, 13' thus produced are enlarged with respect to the narrow flame strips 14 and are about circular in plan view. Herein, the secondary air supply to the flame strips 14 is improved in that the impressions 10, 10 serving to produce the adhering flames 13, 13 are only provided at each second gas outlet slot 12, 12'.

It is, of course, also possible to provide only one impression 10' at the left side of one gas outlet slot, such as 12, and one impression 10 at the right side of an adjoining gas outlet slot such as 12" thereby providing each burner slot with one impression and permitting adjoining burner slots to be relatively closely spaced.

The invention is claimed as follows:

1. In a gaseous fuel burner, the improvement comprising: a piece of sheet material having generally flat portions with a plurality of elongate and generally parallel spaced slots therein for emitting gaseous fuel, said slots having opposite and spaced apart end portions, said plate also having a concave depression substantially intersected by one of said end portions for causing the fuel to flow therefrom in a converging manner, thereby creating turbulent flow from said concave depression and a lesser rate of fuel flow therefrom than from other portions of said slot.

2. The burner as defined in claim 1, wherein said concave depression com-prises an elongate trough extending generally perpendicularly of said slots.

3. The burner as defined in claim 1, wherein said piece of sheet material has a plurality of depressions, each of said depressions being generally cup-shaped and each being substantially intersected by a different slot.

4. A gas burner, comprising: a main body forming a mixing tube for gaseous fuel; a cover plate of sheet metal attached to said body and forming an enclosure with said main body, said cover plate having a substantially flat area with a plurality of generally parallel and elongate slots therein adjacent one another comprising fuel outlets, each of said slots having spaced apart end portions, said flat area also having a plurality of spaced concave depressions formed therein of generally U-shaped cross-section, each of said depressions being substantially intersected by the end portions of one of said slots thereby forming outwardly diverging gas outlet areas at said slot end portions which thereby cause gas flowing therefrom to converge and create turbulence resulting in a reduced rate of gas flow from said intersected end portions.

5. A gas burner, comprising: a main body forming a mixing tube for gaseous fuel; a cover plate of sheet metal attached to said body and forming an enclosure with said main body, said cover plate having a substantially flat area with a plurality of generally parallel and elongate slots therein adjacent one another comprising fuel outlets, each of said slots being defined by spaced apart end portions, said flat area having a pair of elongate and spaced concave depressions formed therein of generally U-shaped cross-section, each of said depressions extending transversely of said slots and being substantially intersected by one end portion of each slot thereby forming outwardly diverging gas outlet areas in said end portions which cause gas flowing therefrom to converge and create turbulence resulting in a reduced rate of gas flow from said intersected end portions.

References Cited by the Examiner UNITED STATES PATENTS 640,698 1/1900 Porter 67-1 12 1,095,280 5/1914 Keller 67112 1,204,278 11/1916 Keller 67-112 1,424,739 8/1922 Reeves 158116 2,016,866 10/1935 Lurie 158-116 2,237,889 5/1941 Rickert 158l16 2,588,895 3/1952 Tavener 158116 FREDERICK L. MATTESON, JR., Primary Examiner. 

1. IN A GASEOUS FUEL BURNER, THE IMPROVEMENT COMPRISING: A PIECE OF SHEET MATERIAL HAVING GENERALLY FLAT PORTIONS WITH A PLURALITY OF ELONGATE AND GENERALLY PARALLEL SPACED SLOTS THEREIN FOR EMITTING GASEOUS FUEL, SAID SLOTS HAVING OPPOSITE AND SPACED APART END PORTIONS, SAID PLATE ALSO HAVING A CONCAVE DEPRESSION SUBSTANTIALLY INTERSECTED BY ONE OF SAID END PORTIONS FOR CAUSING THE FUEL TO FLOW THEREFROM IN A CONVERGING MANNER, THEREBY CREATING TURBULENT FLOW FROM SAID CONCAVE DEPRESSION AND A LESSER RATE OF FUEL FLOW THEREFROM THAN FROM OTHER PORTIONS OF SAID SLOT. 